This is a good cautionary tale. Any mill will be happy to pop into the mail a twist of each of the available thread colors, plus reasonable alternates. So, you should always ask just to make sure that you and the mill are on the same page WRT colors.

I will also say that I learned many years ago from my photographer husband that two color photographs of the same scene, one taken with Kodachrome and the other with Ektachrome (which each had a different color balance, for those of you who don't remember the time of film cameras....), look equally great when looked at separately. But, put them together, and - whoa - they look really different from one another. Looked at side by side, you might very well like one better than the other, even though a minute ago, you thought they were both great when you looked at them separately.

I mention this because we had something of the same issue with the Wildcat tartan. We couldn't match the original tartan as designed on the computer, and we had to make some compromises on thread color. Put side by side, the paper printout of the original design and the finished tartan are quite a bit different. But, looked at by itself, each is fabulous. So, unless you are trying to match a previous length of tartan (as KD Burke was), get as close as you can with the colors, and then put away the computer printout and love your tartan.